declare
local
   class ForwardMixin
      attr Forward:none
      meth setForward(F) Forward:=F end
      meth otherwise(M)
         if @Forward==none then raise undefinedMethod end
         else {@Forward M} end
      end
   end
in
   fun {NewF Class Init}
      {New class $ from Class ForwardMixin end Init}
   end
end
